static unsigned int
signal_poll(struct file * filp,
struct poll_table_struct * poll)
{
struct xpmem_thread_group * seg_tg;
struct xpmem_segment * seg;
xpmem_segid_t segid;
unsigned long irqs;
unsigned int mask = 0;
segid = (xpmem_segid_t)filp->private_data;
seg_tg = xpmem_tg_ref_by_segid(segid);
if (IS_ERR(seg_tg))
return PTR_ERR(seg_tg);
seg = xpmem_seg_ref_by_segid(seg_tg, segid);
if (IS_ERR(seg)) {
xpmem_tg_deref(seg_tg);
return PTR_ERR(seg);
}
poll_wait(filp, &(seg->signalled_wq), poll);
irqs = atomic_read(&(seg->irq_count));
if (irqs > 0)
mask = POLLIN | POLLRDNORM;
xpmem_seg_deref(seg);
xpmem_tg_deref(seg_tg);
return mask;
}
static ssize_t
signal_write(struct file * filp,
const char __user * buffer,
size_t length,
loff_t * offset)
{
struct xpmem_thread_group * seg_tg;
struct xpmem_segment * seg;
xpmem_segid_t segid;
unsigned long irqs;
unsigned long acks;
int status;
if (length != sizeof(unsigned long))
return -EINVAL;
status = copy_from_user(&acks, buffer, sizeof(unsigned long));
if (status)
return status;
segid = (xpmem_segid_t)filp->private_data;
seg_tg = xpmem_tg_ref_by_segid(segid);
if (IS_ERR(seg_tg))
return PTR_ERR(seg_tg);
seg = xpmem_seg_ref_by_segid(seg_tg, segid);
if (IS_ERR(seg)) {
xpmem_tg_deref(seg_tg);
return PTR_ERR(seg);
}
irqs = atomic_read(&(seg->irq_count));
if (acks > irqs)
acks = irqs;
atomic_sub(acks, &(seg->irq_count));
xpmem_seg_deref(seg);
xpmem_tg_deref(seg_tg);
return length;
}
static ssize_t
signal_read(struct file * filp,
char __user * buffer,
size_t length,
loff_t * offset)
{
struct xpmem_thread_group * seg_tg;
struct xpmem_segment * seg;
xpmem_segid_t segid;
unsigned long irqs;
int err;
if (length != sizeof(unsigned long))
return -EINVAL;
segid = (xpmem_segid_t)filp->private_data;
seg_tg = xpmem_tg_ref_by_segid(segid);
if (IS_ERR(seg_tg))
return PTR_ERR(seg_tg);
seg = xpmem_seg_ref_by_segid(seg_tg, segid);
if (IS_ERR(seg)) {
xpmem_tg_deref(seg_tg);
return PTR_ERR(seg);
}
/* Only ack if there are pending notifications */
err = (atomic_add_unless(&(seg->irq_count), -1, 0) == 0);
irqs = atomic_read(&(seg->irq_count));
xpmem_seg_deref(seg);
xpmem_tg_deref(seg_tg);
if (err)
return -ENODEV;
if (copy_to_user(buffer, &irqs, sizeof(unsigned long)))
return -EFAULT;
return length;
}
static ssize_t
signal_read(struct file * filp,
char __user * buffer,
size_t length,
loff_t * offset)
{
struct xpmem_thread_group * seg_tg;
struct xpmem_segment * seg;
xpmem_segid_t segid;
unsigned long irqs;
if (length != sizeof(unsigned long))
return -EINVAL;
segid = (xpmem_segid_t)filp->private_data;
seg_tg = xpmem_tg_ref_by_segid(segid);
if (IS_ERR(seg_tg))
return PTR_ERR(seg_tg);
seg = xpmem_seg_ref_by_segid(seg_tg, segid);
if (IS_ERR(seg)) {
xpmem_tg_deref(seg_tg);
return PTR_ERR(seg);
}
wait_event_interruptible(seg->signalled_wq,
(atomic_read(&(seg->irq_count)) > 0)
);
irqs = atomic_read(&(seg->irq_count));
atomic_set(&(seg->irq_count), 0);
xpmem_seg_deref(seg);
xpmem_tg_deref(seg_tg);
if (copy_to_user(buffer, &irqs, sizeof(unsigned long)))
return -EFAULT;
return length;
}
int
xpmem_segid_signal(xpmem_segid_t segid)
{
struct xpmem_thread_group * seg_tg;
struct xpmem_segment * seg;
seg_tg = xpmem_tg_ref_by_segid(segid);
if (IS_ERR(seg_tg))
return PTR_ERR(seg_tg);
seg = xpmem_seg_ref_by_segid(seg_tg, segid);
if (IS_ERR(seg)) {
xpmem_tg_deref(seg_tg);
return PTR_ERR(seg);
}
xpmem_seg_signal(seg);
xpmem_seg_deref(seg);
xpmem_tg_deref(seg_tg);
return 0;
}
/*
* Get permission to access a specified segid.
*/
int
xpmem_get(xpmem_segid_t segid, int flags, int permit_type, void *permit_value,
xpmem_apid_t *apid_p)
{
xpmem_apid_t apid = 0;
int status = 0;
int shadow_seg = 0;
struct xpmem_segment *seg = NULL;
struct xpmem_thread_group *ap_tg, *seg_tg;
if (segid <= 0)
return -EINVAL;
if ((flags & ~(XPMEM_RDONLY | XPMEM_RDWR)) ||
(flags & (XPMEM_RDONLY | XPMEM_RDWR)) ==
(XPMEM_RDONLY | XPMEM_RDWR))
return -EINVAL;
switch (permit_type) {
case XPMEM_PERMIT_MODE:
case XPMEM_GLOBAL_MODE:
if (permit_value != NULL)
return -EINVAL;
break;
default:
return -EINVAL;
}
/* There are 2 cases that result in a remote lookup:
* (1) The thread group encoded in the segment does not exist locally.
*
* (2) The thread group exists locally, but the segment does not. The
* ids for thread groups are not globally unique, so it's possible that
* the same thread group id exists in two separate enclaves, but only
* one will own the segment
*/
seg_tg = xpmem_tg_ref_by_segid(segid);
if (IS_ERR(seg_tg)) {
seg_tg = xpmem_tg_ref_by_gid(current->aspace->id);
if (IS_ERR(seg_tg))
return PTR_ERR(seg_tg);
shadow_seg = 1;
}
if (!shadow_seg) {
seg = xpmem_seg_ref_by_segid(seg_tg, segid);
if (IS_ERR(seg))
shadow_seg = 1;
}
if (shadow_seg) {
/* No local segment found. Look for a remote one */
/* NOTE: in either case, the tg has already been ref'd. We ref the
* current process' tg if no tg is found for the segid
*/
status = xpmem_try_get_remote(seg_tg, segid, flags, permit_type,
permit_value);
if (status != 0) {
xpmem_tg_deref(seg_tg);
return status;
}
/* Now, get the shadow segment */
seg = xpmem_seg_ref_by_segid(seg_tg, segid);
if (IS_ERR(seg)) {
/* Error should be impossible here, but we'll
* check anyway. The shadow segment was created in
* xpmem_try_get_remote, so destroy it here */
xpmem_remove(segid);
xpmem_tg_deref(seg_tg);
return PTR_ERR(seg);
}
}
/* find accessor's thread group structure */
ap_tg = xpmem_tg_ref_by_gid(current->aspace->id);
if (IS_ERR(ap_tg)) {
BUG_ON(PTR_ERR(ap_tg) != -ENOENT);
status = -XPMEM_ERRNO_NOPROC;
goto err_ap_tg;
}
apid = xpmem_make_apid(ap_tg);
if (apid < 0) {
status = apid;
goto err_apid;
}
status = xpmem_get_segment(flags, permit_type, permit_value, apid,
seg, seg_tg, ap_tg);
if (status != 0)
goto err_get;
*apid_p = apid;
xpmem_tg_deref(ap_tg);
/*
* The following two derefs
*
* xpmem_seg_deref(seg);
* xpmem_tg_deref(seg_tg);
*
* aren't being done at this time in order to prevent the seg
* and seg_tg structures from being prematurely kmem_free'd as long as the
* potential for them to be referenced via this ap structure exists.
*
* These two derefs will be done by xpmem_release_ap() at the time
* this ap structure is destroyed.
*/
return status;
err_get:
err_apid:
xpmem_tg_deref(ap_tg);
err_ap_tg:
/* If we created a shadow segment, destroy it on error. Else, just
* deref it
*/
if (shadow_seg)
xpmem_remove(segid);
else
xpmem_seg_deref(seg);
xpmem_tg_deref(seg_tg);
return status;
}
